2008/11/26 Arteriovenous Access for Hemodialysis 報告醫師 R2 黃民評 指導醫師 王逸淳 蘇鈺壬 邱千華

2008/11/26 AV fistula

2008/11/26 AV graft

2008/11/26 Why AV fistulas are better than grafts Less hyperplesia of veinous intima → less stenosis and eventual obstruction → higher long term patent rate Fewer inectious rate Guidelines suggestion Early access evaluation and construction Preoperative imaging

2008/11/26 Anticipating the need for AV access Progressive renal failure GFR < 30 ml/min/1.73 m 2 Peritoneal dialysis : back up AV fistula ? Kidney transplantation : < 6 months PICC : risk of central vein steosis

2008/11/26 Preoperative evaluation Past history Physical examination Image studies Doppler ultrasonography Venography Arteriography Magnetic resonance Minimal vein and artery size Vein dilation test Arterial dilation test Brachial artery flow Mapping

2008/11/26 AV fistula Location ： wrist radiocephalic or Brescia-Cimino fistula Construction ： side-of-artery-to-end-of-vein anastomosis Perioperative care and maturation ： Blood flow should be checked daily Never be used for venipuncture Hand exercises requires at least 1 month blood flow <350 mL per minute 6 or more weeks after placement, an imaging fistulogram should be obtained

2008/11/26 AV grafts Expanded polytetrafluoroethylene (PTFE) Location End of the graft and side of vein or artery Maturation ： at least 2~3 weeks

2008/11/26 General issues relating to both AV fistulas and grafts Cannulation Complications Clinical outcome goals and monitoring

2008/11/26 Cannulation Skin preparation, Anesthesia, Tourniquets Needle size, position and orientation Risk of inflow/outflow needle reversal Repeated punctures: Needle rotation, buttonhole technique Hemostasis postdialysis

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Complication ： stenosis Clinical indicators ： Recurrent clotting (twice a month or more) Difficult needle placement (strictures) Difficulty with hemostasis on needle withdrawal (intra-access hypertension) Persistently swollen arm, Reduction in the urea reduction ratio (URR) or Kt/V Increase in intensity of the thrill or the pitch of the bruit

2008/11/26 Complication ： stenosis Access recirculation Imaging the vascular access Doppler ultrasonography, Venography Intervention after access stenosis percutaneous transluminal catheter angioplasty (PTCA) or surgical revision

2008/11/26 Complication ： thrombosis Predisposing factors Prevention Anticoagulants and antiplatelet drug New PTFE grafts with dipyridamole ACEI and daily fish oil supplementation Implant irradiation

2008/11/26 Complication ： thrombosis Treatment In AV fistla - early thrombosis, late thrombosis - PTCA, surgical thrombectomy In AV graft - Surgical thrombectomy, mechanical or pharmaco-mechenical thrombolysis - evaluated for hypercoagulability delayed hypotension after dialysis - secondary fistula creation

2008/11/26 Complication ： Ischemia in a limb bearing an AV access Detection ： 5p - pain, coldness, numbness, tingling, impairment of motor function - changes in skin temperature and color loss of sensary/motor function, distal pulses edema in the hand or arm Steal effect Nonhealing ulcer, nerve injury Distal revascularization interval ligation (DRIL) 疼痛 (pain) 無脈博 (pulseless) 蒼白 (pallor) 感覺異常 (paresthesia) 麻痺 (paralysis)

2008/11/26 Complication ： Pseudoaneurysm AV fistula ： observation, avoiding puncture AV graft ： treated by resection and insertion of an interposition graft if they are (a)rapidly expanding (b)>12 mm in diameter (c)threatening viability of the overlying skin

2008/11/26 Complication ： Infection AV fistula - staphylococci - 6 weeks of antibiotics AV graft - occurs eventually in 5% ~ 20% - Prophylactic antimicrobials - against G(-) and G(+) organisms as well as against Enterococcus - Septicemia may occur without local signs

2008/11/26 Complication ： Congestive heart failure Wrist and forearm < Upper arm < Femoral Surgical narrowing or banding vasodilators (minoxidil or hydralazine ) without concomitant beta-blockade

2008/11/26 Clinical outcome goals and monitoring Establishment of a vascular access team and continuous quality improvement (CQI) Maximizing AV fistula placement at least 60% of all patients new to H/D Goals for AV graft placement Failure rates, Cumulative patency rates Rate of graft thrombosis Goals for limiting use of venous catheters

2008/11/26 Thanks for your attention